The kg is dead, long live the kg

Today (Friday), representatives from nearly 60 nations are meeting in Versailles, France, to vote to change the definition of a kilogram, as well as changing the fundamental unit of temperature (Kelvin), the unit for an amount of substance (mole), and the unit for electric current (ampere). Going forward, all SI units will be based on fundamental constants of nature rather than physical artifacts. Here, get the details on these changes and what they mean for the physics community.